Thruline RF Power Meter, Model 4421
39
Replacing Batteries
There are two battery configurations in the 4421 Power Meter. In the larger case models (before 2016), the
batteries are horizontally arranged, in units with a smaller case the batteries are vertically arranged in a battery
assembly.
Replace Batteries (Older models)
1.
Disconnect the AC power cord from the AC mains supply.
2.
Remove the four screws that secure the top cover.
3.
Lift the top cover to access the attached ground wire.
4.
Disconnect the ground wire.
5.
Remove the cover.
6.
Unfasten the battery retaining belts (
Figure
18
).
7.
Remove the battery tubes.
Note:
Be sure to note the polarity and orientation of the battery tubes before removing them.
8.
Remove the batteries from each tube.
9.
Insert replacement batteries.
Note:
Be sure to note the polarity (positive and negative) arrangement of the batteries.
10. Install the battery tubes into the unit and secure with the retaining belts.
Note:
Be sure to position the retaining belts as they were before removal and tighten them securely.
11. Connect the ground wire to the top cover.
12. Install the top cover.
13. Secure top cover with the four screws removed earlier.
WARNING
Exposed AC line voltage (115 VAC or 230 VAC). Disconnect the power cord from the
AC line before replacing the batteries. Failure to comply may result in severe
electrical shock or death.
WARNING
Use only Nickel Metal Hydride (NiMH) batteries that have a minimum capacity of 4500
milliampere hours (mAh). Do not install batteries that are not Nickel Metal Hydride.
Do not install NiMH batteries that have less than 4500 mAh capacity. Failure to
comply may result in damage to the batteries, damage to the instrument, and injury
to personnel from battery chemicals.
